The present invention relates to bicyclic acyl guanidine compounds which are sodium/proton exchange (NHE) inhibitors and are useful as antianginal agents, and cardioprotective agents and for treating peripheral vascular disease including intermittent claudication.
In accordance with the present invention, novel bicyclic acyl guanidines are provided which are sodium/proton exchange (NHE) inhibitors and have the structure I 
including pharmaceutically acceptable salts thereof, all stereoisomers thereof, and prodrug esters thereof,
wherein
R1 and R2 are the same or different and are independently H, alkyl, alkenyl, alkynyl, alkoxy, alkenyloxy, alkynyloxy, (alkyl or aryl)3Si (where each alkyl or aryl group is independent), cycloalkyl, cycloalkenyl, aryl, arylalkyl, aryloxy, cycloheteroalkyl, cycloheteroalkylalkyl, heteroaryl, heteroaryloxy, arylthio, arylsulfinyl, arylsulfonyl, thio, alkylthio, alkylsulfinyl, alkylsulfonyl, heteroarylthio, heteroarylsulfinyl, hetero-arylsulfonyl, halogen, haloalkyl, polyhaloalkyl such as CF3 and CF3CH2, polyhaloalkyloxy such as CF3O and CF3CH2O, alkylaminocarbonyl, arylaminocarbonyl, heteroarylaminocarbonyl, acyl, carboxy, aminocarbonyl, alkylcarbonyl, alkoxycarbonyl, arylcarbonyl, heteroarylcarbonyl, cyano, tetrazolyl, imidazole, oxazole or triazole, xe2x80x94PO(R8) (R9), S(O)2R8, R9 (where R1 and R9 are the same or different and are independently hydrogen, alkyl, aryl, alkoxy, aryloxy, cycloalkyl, heteroaryl, heteroarylalkyl, heteroaryloxy, heteroarylalkoxy, cycloheteroalkyl, cycloheteroalkylalkyl, cycloheteroalkoxy, or cycloheteroalkylalkoxy);
Additionally R1 and R2 can be optionally joined together to form a non-aromatic substituted or unsubstituted carbocyclic ring (namely, a cycloalkyl or cycloalkenyl ring), or a cycloheteroalkyl ring (which includes one, two or three hetero atoms such as O, S and/or N), which ring contains 3 to 8 members.
X is a bond, O, S, SO, SO2, CO, 
xe2x80x83or NR7 (wherein R7 is H, lower alkyl, alkanoyl, or xe2x80x94SO2alkyl);
Y is a bond, O, S, SO, SO2, CO, 
xe2x80x83or NR7xe2x80x2 (wherein R7xe2x80x2 is H, lower alkyl, alkanoyl, or SO2alkyl);
n is an integer from 1 to 4;
nxe2x80x2 is an integer from 1 to 4; with the proviso that at least one of X and Y is other than a bond;
Ra, Rb, Rc and Rd may be the same or different and are any of the groups set out under the definition of R1 and R2, and may be the same as or different from R1 or R2;
where n is  greater than 1 and/or nxe2x80x2 greater than 1, then in the repeating 
xe2x80x83groups, Ra and Rb in repeating groups may be the same of different, and Rc and Rd in repeating groups may be the same or different.
R3, R4, R5 and R6 are the same or different and are independently selected from H, alkyl, alkenyl, alkynyl, alkoxy, alkenyloxy, alkynyloxy, (alkyl or aryl)3Si (where each alkyl or aryl group is independent), cycloalkyl, cycloalkenyl, aryl, arylalkyl, aryloxy, cycloheteroalkyl, cycloheteroalkylalkyl, heteroaryl, heteroaryloxy, arylthio, arylsulfinyl, arylsulfonyl, thio, alkylthio, alkylsulfinyl, alkylsulfonyl, heteroarylthio, heteroarylsulfinyl, hetero-arylsulfonyl, halogen, haloalkyl, polyhaloalkyl such as CF3 and CF3CH2, polyhaloalkyloxy such as CF3O and CF3CH2O, acyl, carboxy, aminocarbonyl, alkylcarbonyl, alkoxycarbonyl, arylcarbonyl, heteroarylcarbonyl, cyano, tetrazolyl, imidazole, oxazole or triazole, xe2x80x94PO(R12) (R13), S(O)2R12, R13 (where R12 and R13 are the same or different and are independently hydrogen, alkyl, aryl, alkoxy, aryloxy, cycloalkyl, heteroaryl, heteroarylalkyl, heteroaryloxy, heteroarylalkoxy, cycloheteroalkyl, cycloheteroalkylalkyl, cycloheteroalkoxy, or cycloheteroalkylalkoxy), amino, alkylamino, alkenylamino, alkynylamino, arylalkylamino, arylamino, heteroarylamino, thio, alkylsulfonylamino, alkenylsulfonylamino, alkynylsulfonylamino, arylsulfonylamino, heteroarylsulfonylamino, alkylaminocarbonyl, arylaminocarbonyl, heteroarylaminocarbonyl, hydroxy, alkylcarbonyloxy, alkylcarbonylamino, arylcarbonyloxy, arylcarbonylamino, heteroarylcarbonyloxy, heteroarylcarbonylamino, nitro, alkenylcarbonylamino, alkynylcarbonylamino, alkylaminocarbonylamino, alkenylaminocarbonylamino, alkynylaminocarbonylamino, arylaminocarbonylamino, heteroarylaminocarbonylamino, alkoxycarbonylamino, alkenyloxycarbonylamino, alkynyloxycarbonylamino, aryloxycarbonylamino, heteroaryloxycarbonylamino, aminocarbonylamino, alkylaminocarbonyloxy, 1,1-(alkoxyl or aryloxy)2alkyl (where the two aryl or alkyl substituents can be independently defined, or linked to one another to form a ring, such as 1,3-dioxane or 1,3-dioxolane), xe2x80x94NR10(Cxe2x95x90NR11)alkyl, xe2x80x94NR10(Cxe2x95x90NR11)alkenyl, xe2x80x94NR10(Cxe2x95x90NR11)alkynyl, xe2x80x94NR10(Cxe2x95x90NR11)heteroaryl, or xe2x80x94NR10(Cxe2x95x90NCN)-amino;
R10 and R11 are the same or different and are independently hydrogen, alkyl, haloalkyl, aryl, alkoxy, aryloxy, cycloalkyl, heteroaryl, arylalkyl, or cycloheteroalkyl.
Additionally any two adjacent R4, R5 and R6 substituents can be joined together to form an aromatic or non-aromatic, substituted or unsubstituted ring (such as a cycloalkyl or cycloalkenyl ring), a cycloheteroalkyl ring or a heteroaryl ring, which ring contains 5 to 8 members.
Preferred are compounds of formula I of the invention wherein Y is a bond; that is 
Preferably X is O or S; more preferably, X is O; preferably R1 and R2 are the same or different and are independently hydrogen, lower alkyl, perhaloalkyl, halogen, lower alkoxy, or aryl, at least one of R1 and R2 being other than hydrogen; more preferably R1 and R2 are the same or different and are independently hydrogen, lower alkyl, or perhaloalkyl, and R3 is H; preferably R4, R5 and R6 are the same or different and are independently H, lower alkyl, lower alkoxy, aryl, perhaloalkyl, or halogen; more preferably R4, R5 and R6 are the same or different and are independently hydrogen, lower alkyl,lower alkoxy or halogen.
Preferred examples of R1 and R2 groups include methyl, ethyl, isopropyl, t-butyl, trifluoromethyl or phenyl. Preferred examples of R4, R5 and R6 groups include fluoro, chloro, methyl, trifluoromethyl or methoxy.
In addition, in accordance with the present invention, methods for preventing, inhibiting or treating angina (stable or unstable), cardiac dysfunction, myocardial necrosis, arrhythmia, peripheral vascular disease including intermittent claudication are provided, wherein a compound of formula I of the invention is administered in a therapeutically effective amount which inhibits sodium/proton exchange.
In addition, a method is provided for the relief of symptoms of pain, parethesia or discomfort in the lower limb and gluteal regions produced by arterial insufficiency where symptoms are initiated or worsened with ambulation, which includes the step of administering to a mammalian species in need of treatment a therapeutically effective amount of a compound of formula I.
The following definitions apply to the terms as used throughout this specification, unless otherwise limited in specific instances.
Unless otherwise indicated, the term xe2x80x9clower alkylxe2x80x9d, xe2x80x9calkylxe2x80x9d or xe2x80x9calkxe2x80x9d as employed herein alone or as part of another group includes both straight and branched chain hydrocarbons, containing 1 to 40 carbons, preferably 1 to 20 carbons, more preferably 1 to 12 carbons, in the normal chain,such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl, the various additional branched chain isomers thereof, and the like as well as such groups including 1 to 4 substituents which may be halo, for example F, Br, Cl or CF3, alkoxy, aryl, aryloxy, aryl(aryl) or diaryl, arylalkyl, arylalkyloxy, alkenyl, cycloalkyl, cycloalkylalkyl, cycloalkylalkyloxy, amino, hydroxy, hydroxyalkyl, acyl, heteroaryl, heteroaryloxy, nitro, cyano, haloalkyl, polyhaloalkyl (or perhaloalkyl) and/or alkylthio and/or any of the R1 groups.
Unless otherwise indicated, the term xe2x80x9ccycloalkylxe2x80x9d as employed herein alone or as part of another group includes saturated or partially unsaturated (containing 1 or 2 double bonds) cyclic hydrocarbon groups containing 1 to 3 rings, including monocyclicalkyl, bicyclicalkyl and tricyclicalkyl, containing a total of 3 to 20 carbons forming the rings, preferably 4 to 12 carbons, forming the ring and which may be fused to one aromatic ring as described for aryl; examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl and cyclododecyl, cyclohexenyl, 
any of which groups may be optionally substituted with 1 to 4 substituents which may be any of the substituents set out for alkyl.
The term xe2x80x9ccycloalkenylxe2x80x9d as employed herein alone or as part of another group refers to cyclic hydrocarbons containing 5 to 20 carbons, preferably 6 to 12 carbons and 1 or 2 double bonds. Exemplary cycloalkenyl groups include cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, cyclohexadienyl, and cycloheptadienyl, which may be optionally substituted as defined for cycloalkyl.
The term xe2x80x9carylxe2x80x9d as employed herein alone or as part of another group refers to monocyclic and bicyclic aromatic groups containing 6 to 10 carbons in the ring portion (such as phenyl or naphthyl including 1-naphthyl and 2-naphthyl) and may optionally include one to three additional rings fused to a carbocyclic ring or a heterocyclic ring (such as aryl, cycloalkyl, heteroaryl or cycloheteroalkyl rings) and may be optionally substituted through available carbon atoms with 1, 2, or 3 groups selected from hydrogen, halo, haloalkyl, alkyl, polyhaloalkyl, alkoxy, haloalkoxy, alkenyl, trifluoromethyl, trifluoromethoxy, alkynyl, cycloalkyl-alkyl, cycloheteroalkyl, cycloheteroalkylalkyl, aryl, heteroaryl, arylalkyl, aryloxy, aryloxyalkyl, arylalkoxy, arylthio, arylazo, heteroarylalkyl, heteroarylalkenyl, heteroarylheteroaryl, heteroaryloxy, hydroxy, nitro, cyano, amino, substituted amino wherein the amino includes 1 or 2 substituents (which are alkyl, aryl or any of the other aryl compounds mentioned in the definitions), thiol, alkylthio, arylthio, heteroarylthio, arylthioalkyl, alkoxyarylthio, alkylcarbonyl, arylcarbonyl, alkyl-aminocarbonyl, arylaminocarbonyl, alkoxycarbonyl, aminocarbonyl, alkylcarbonyloxy, arylcarbonyloxy, alkylcarbonylamino, arylcarbonylamino, arylsulfinyl, arylsulfinylalkyl, arylsulfonylamino or arylsulfon-aminocarbonyl, or any of the substituents set out for alkyl.
The term xe2x80x9caralkylxe2x80x9d, xe2x80x9caryl-alkylxe2x80x9d or xe2x80x9caryllower alkylxe2x80x9d as used herein alone or as part of another group refers to alkyl groups as discussed above having an aryl substituent, such as benzyl or phenethyl, or naphthylpropyl, or an aryl as defined above.
The term xe2x80x9clower alkoxyxe2x80x9d, xe2x80x9calkoxyxe2x80x9d, xe2x80x9caryloxyxe2x80x9d or xe2x80x9caralkoxyxe2x80x9d as employed herein alone or as part of another group includes any of the above alkyl, aralkyl or aryl groups linked to an oxygen atom.
The term xe2x80x9caminoxe2x80x9d as employed herein alone or as part of another group may optionally be independently substituted with one or two substituents (substituted amino), which may be the same or different, such as alkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, cycloheteroalkyl, cycloheteroalkylalkyl, cycloalkyl, cycloalkylalkyl, haloalkyl, hydroxyalkyl, alkoxyalkyl or thioalkyl. These substituents may be further substituted with a carboxylic acid or substituents for alkyl as set out above. In addition, the amino substituents may be taken together with the nitrogen atom to which they are attached to form 1-pyrrolidinyl, 1-piperidinyl, 1-azepinyl, 4-morpholinyl, 4-thiamorpholinyl, 1-piperazinyl, 4-alkyl-1-piperazinyl, 4-arylalkyl-1-piperazinyl, 4-diarylalkyl-1-piperazinyl, 1-pyrrolidinyl, 1-piperidinyl, or 1-azepinyl, optionally substituted with alkyl, alkoxy, alkylthio, halo, trifluoromethyl or hydroxy.
The term xe2x80x9clower alkylthioxe2x80x9d, alkylthioxe2x80x9d, xe2x80x9carylthioxe2x80x9d or xe2x80x9caralkylthioxe2x80x9d as employed herein alone or as part of another group includes any of the above alkyl, aralkyl or aryl groups linked to a sulfur atom.
The term xe2x80x9clower alkylaminoxe2x80x9d, xe2x80x9calkylaminoxe2x80x9d, xe2x80x9carylaminoxe2x80x9d, or xe2x80x9carylalkylaminoxe2x80x9d as employed herein alone or as part of another group includes any of the above alkyl, aryl or arylalkyl groups linked to a nitrogen atom.
The term xe2x80x9cacylxe2x80x9d as employed herein by itself or part of another group, as defined herein, refers to an organic radical linked to a carbonyl 
group; examples of acyl groups include any of the R1 groups attached to a carbonyl, such as alkanoyl, alkenoyl, aroyl, aralkanoyl, heteroaroyl, cycloalkanoyl, cycloheteroalkanoyl and the like.
The term xe2x80x9calkanoylxe2x80x9d as used herein alone or as part of another group refers to alkyl linked to a carbonyl group.
Unless otherwise indicated, the term xe2x80x9clower alkenylxe2x80x9d or xe2x80x9calkenylxe2x80x9d as used herein by itself or as part of another group refers to straight or branched chain radicals of 2 to 20 carbons, preferably 3 to 12 carbons, and more preferably 1 to 8 carbons in the normal chain, which include one to six double bonds in the normal chain, such as vinyl, 2-propenyl, 3-butenyl, 2-butenyl, 4-pentenyl, 3-pentenyl, 2-hexenyl, 3-hexenyl, 2-heptenyl, 3-heptenyl, 4-heptenyl, 3-octenyl, 3-nonenyl, 4-decenyl, 3-undecenyl, 4-dodecenyl, 4,8,12-tetradecatrienyl, and the like, and which may be optionally substituted with 1 to 4 substituents, namely, halogen, haloalkyl, alkyl, alkoxy, alkenyl, alkynyl, aryl, arylalkyl, cycloalkyl, amino, hydroxy, heteroaryl, cycloheteroalkyl, alkanoylamino, alkylamido, arylcarbonyl-amino, nitro, cyano, thiol, alkylthio or any of the substituents for alkyl.
Unless otherwise indicated, the term xe2x80x9clower alkynylxe2x80x9d or xe2x80x9calkynylxe2x80x9d as used herein by itself or as part of another group refers to straight or branched chain radicals of 2 to 20 carbons, preferably 2 to 12 carbons and more preferably 2 to 8 carbons in the normal chain, which include one triple bond in the normal chain, such as 2-propynyl, 3-butynyl, 2-butynyl, 4-pentynyl, 3-pentynyl, 2-hexynyl, 3-hexynyl, 2-heptynyl, 3-heptynyl, 4-heptynyl, 3-octynyl, 3-nonynyl, 4-decynyl, 3-undecynyl, 4-dodecynyl and the like, and which may be optionally substituted with 1 to 4 substituents, namely, halogen, haloalkyl, alkyl, alkoxy, alkenyl, alkynyl, aryl, arylalkyl, cycloalkyl, amino, heteroaryl, cycloheteroalkyl, hydroxy, alkanoylamino, alkylamido, arylcarbonylamino, nitro, cyano, thiol, and/or alkylthio, or any of the substituents for alkyl.
Where alkyl groups as defined above have single bonds for attachment to other groups at two different carbon atoms, they are termed xe2x80x9calkylenexe2x80x9d groups and may optionally be substituted as defined above for xe2x80x9calkylxe2x80x9d.
Where alkenyl groups as defined above and alkynyl groups as defined above, respectively, have single bonds for attachment at two different carbon atoms, they are termed xe2x80x9calkenylene groupsxe2x80x9d and xe2x80x9calkynylene groupsxe2x80x9d, respectively, and may optionally be substituted as defined above for xe2x80x9calkenylxe2x80x9d and xe2x80x9calkynylxe2x80x9d.
Suitable alkylene, alkenylene or alkynylene groups (CH2)p (where p is 1 to 8, preferably 1 to 5) (which may include alkylene, alkenylene or alkynylene groups) as defined herein, may optionally include 1, 2, or 3 substituents which include any of the substituents for alkyl.
Examples of alkylene, alkenylene and alkynylene include 
The term xe2x80x9chalogenxe2x80x9d or xe2x80x9chaloxe2x80x9d as used herein alone or as part of another group refers to chlorine, bromine, fluorine, and iodine as well as CF3, with chlorine or fluorine being preferred.
The term xe2x80x9cmetal ionxe2x80x9d refers to alkali metal ions such as sodium, potassium or lithium and alkaline earth metal ions such as magnesium and calcium, as well as zinc and aluminum.
The term xe2x80x9ccycloheteroalkylxe2x80x9d as used herein alone or as part of another group refers to a 5-, 6- or 7-membered saturated or partially unsaturated ring which includes 1 to 2 hetero atoms such as nitrogen, oxygen and/or sulfur, linked through a carbon atom or a heteroatom, where possible, optionally via the linker (CH2)p (which is defined above), such as 
and the like. The above groups may include 1 to 4 substituents such as alkyl, halo, oxo and/or any of of the substituents for alkyl. In addition, any of the above rings can be fused to a cycloalkyl, aryl, heteroaryl or cycloheteroalkyl ring.
The term xe2x80x9cheteroarylxe2x80x9d as used herein alone or as part of another group refers to a 5- or 6-membered aromatic ring which includes 1, 2, 3 or 4 hetero atoms such as nitrogen, oxygen or sulfur, and such rings fused to an aryl, cycloalkyl, heteroaryl or cycloheteroalkyl ring (e.g. benzothiophenyl, indolyl), and includes possible N-oxides. The heteroaryl group may optionally include 1 to 4 substituents such as any of the substituents for alkyl. Examples of heteroaryl groups include the following: 
and the like.
The term xe2x80x9ccycloheteroalkylalkylxe2x80x9d as used herein alone or as part of another group refers to cycloheteroalkyl groups as defined above linked through a C atom or heteroatom to a (CH2)p chain.
The term xe2x80x9cheteroarylalkylxe2x80x9d or xe2x80x9cheteroarylalkenylxe2x80x9d as used herein alone or as part of another group refers to a heteroaryl group as defined above linked through a C atom or heteroatom to a xe2x80x94(CH2)pxe2x80x94 chain, alkylene or alkenylene as defined above.
The term xe2x80x9cpolyhaloalkylxe2x80x9d or xe2x80x9cperhaloalkylxe2x80x9d as used herein refers to an xe2x80x9calkylxe2x80x9d group as defined above which includes from 2 to 9, preferably from 2 to 5, halo substituents, such as F or Cl, preferably F, such as CF3CH2, CF3 or CF3CF2CH2.
The term xe2x80x9cpolyhaloalkyloxyxe2x80x9d as used herein refers to an xe2x80x9calkoxyxe2x80x9d or xe2x80x9calkyloxyxe2x80x9d group as defined above which includes from 2 to 9, preferably from 2 to 5, halo substituents, such as F or Cl, preferably F, such as CF3CH2O, CF3O or CF3CF2CH2O.
The compounds of formula I can be present as salts, in particular pharmaceutically acceptable salts. If the compounds of formula I have, for example, at least one basic center, they can form acid addition salts. These are formed, for example, with strong inorganic acids, such as mineral acids, for example sulfuric acid, phosphoric acid or a hydrohalic acid, with strong organic carboxylic acids, such as alkanecarboxylic acids of 1 to 4 carbon atoms which are unsubstituted or substituted, for example, by halogen, for example acetic acid, such as saturated or unsaturated dicarboxylic acids, for example oxalic, malonic, succinic, maleic, fumaric, phthalic or terephthalic acid, such as hydroxycarboxylic acids, for example ascorbic, glycolic, lactic, malic, tartaric or citric acid, such as amino acids, (for example aspartic or glutamic acid or lysine or arginine), or benzoic acid, or with organic sulfonic acids, such as (C1-C4)-alkyl- or aryl-sulfonic acids which are unsubstituted or substituted, for example by halogen, for example methane- or p-toluene-sulfonic acid. Corresponding acid addition salts can also be formed having, if desired, an additionally present basic center. The compounds of formula I having at least one acid group (for example COOH) can also form salts with bases. Suitable salts with bases are, for example, metal salts, such as alkali metal or alkaline earth metal salts, for example sodium, potassium or magnesium salts, or salts with ammonia or an organic amine, such as morpholine, thiomorpholine, piperidine, pyrrolidine, a mono-, di- or tri-lower alkylamine, for example ethyl-, tert-butyl-, diethyl-, diisopropyl-, triethyl-, tributyl- or dimethyl-propylamine, or a mono-, di- or trihydroxy lower alkylamine, for example mono-, di- or triethanolamine. Corresponding internal salts may furthermore be formed. Salts which are unsuitable for pharmaceutical uses but which can be employed, for example, for the isolation or purification of free compounds I or their pharmaceutically acceptable salts, are also included.
Preferred salts of the compounds of formula I include monohydrochloride, hydrogensulfate, methanesulfonate, phosphate, nitrate or maleate.
All stereoisomers of the compounds of the instant invention are contemplated, either in admixture or in pure or substantially pure form. The compounds of the present invention can have asymmetric centers at any of the carbon atoms including any one of the R substituents. Consequently, compounds of formula I can exist in enantiomeric or diastereomeric forms or in mixtures thereof. The processes for preparation can utilize racemates, enantiomers or diastereomers as starting materials. When diastereomeric or enantiomeric products are prepared, they can be separated by conventional methods for example, chromatographic or fractional crystallization.
It should be understood that the present invention includes prodrug forms of the compounds of formula I such as alkylesters of acids or any of the prodrugs for guanidines disclosed in U.S. application Ser. No. 08/641,718, filed May 2, 1996, and in U.S. Pat. No. 5,561,146 which are incorporated herein by reference.
The compounds of the instant invention may, for example, be in the free or hydrate form, and may be obtained by methods exemplified by the following descriptions.
The compounds of formula I may be prepared by the preferred processes described in the following reaction schemes. Exemplary reagents and procedures for these reactions appear hereinafter and in the working Examples.
Compounds of formula I of the invention can be prepared from the corresponding carboxylic acids by using the sequence of steps outlined in Scheme 1 set out below. Activation of carboxylic acid 1 with various activating reagents (e.g. 1,1xe2x80x2-carbonyldiimidazole (CDI), thionyl chloride, oxalyl chloride, and the like) (employing a molar ratio of activating agent:acid 1 within the range from about 1:1 to about 10:1) in an organic solvent such as THF or methylene chloride, convert acids 1 to 2. Subsequent treatment of compounds of formula 2 with guanidine in DMF or THF (employing a molar ratio of guanidine:2 within the range from about 1:1 to about 20:1) gives compounds of the formula I.
The carboxylic acids of formula 1 can either be commercially available or they can be prepared by methods known in the art or via the routes shown in Schemes 2, 3, 4, 5, 6 and 7. 
(L=a leaving group such as halide, alkoxy, aryloxy or imidazolyl).
Compounds of formula IA of the invention where X is O, Y is a bond, and R2 is H can be prepared as shown in Scheme 2. 
The esters a used in this preparation are either commercially available or they can be prepared by methods known to those skilled in the art. Thus, condensation of esters 3 with the acid chlorides gives 4 which upon reduction and elimination yields esters 5. Treatment of esters 5 with guanidine in an appropriate solvent such as dimethylformamide gives the desired compounds IA of the invention.
Compounds of formula IB of the invention wherein X is O or S, Y is a bond and R2 and R3 are other than H can be prepared as shown in Scheme 3. 
The starting aldehydes 6 are either commercially available or they can be prepared by methods well known to those skilled in the art. Compound 6 is treated with the appropriate acrylic acid ester in the presence of a base such as potassium carbonate to provide a compound of formula 7. Compound 7 is converted to the desired product IB of the invention by deprotection of the acid under appropriate conditions followed by coupling of the resulting acid 8 with guanidine (employing a molar ratio of guanidine:8 within the range from about 1:1 to about 20:1) utilizing a coupling agent such as 1,1xe2x80x2-carbonyldiimidazole.
Compounds of formula IC of the invention wherein X=O or S, Y is 
can be prepared according to Scheme 4. 
The reaction of 9 with 10 in the presence of a base (such as sodium hydride) gives compound of formula 11 which can be converted to the ketone 12 after hydrolysis of the ester and cyclization of the resulting acid. 12 can then be converted to 11 by the carbonylation of the ketone with an agent such as dimethylcarbonate in the presence of a base such as sodium hydride. Compound 15 can be made from 13 by the reduction of the ketone with a reducing agent such as sodium borohydride and hydrolysis of the ester to give 14 which upon treatment with a strong acid such as hydrochloric acid yields 15. The desired compounds of formula 1C of the invention can then be obtained by reacting the acids 15 with guanidine as described in Scheme 2. Compounds of formula 9 are commercially available or they can be prepared by methods described in the literature.
Compounds of formula I of the invention where X is S can be oxidized to the corresponding sulfoxide or sulfone employing oxidizing agents known in the literature, such as m-chloroperbenzoic acid or oxone.
The compounds of formula IA of the invention where X=O or S, and Y is a bond can also be prepared as in Scheme 5. 
The starting phenols or thiols 9 are either commercially available or they can be prepared by methods well known to those skilled in the art. Compound of formula 9 is treated with the diester 16 in the presence of a base such as pyridine. The product of this reaction is then treated with an acid such as polyphosphoric acid (PPA) to provide a compound of formula 17. Compound 17 is converted to the desired product IA in a four step sequence by first treatment with an appropriate organometallic reagent R1MgX, followed by reduction with a reducing agent such as sodium borohydride, treatment of this with an acid such as camphorsulfonic acid in a solvent such as benzene with the azeotropic removal of water followed by treatment of the product with guanidine in an appropriate solvent such as dimethylformamide.
The compounds of formula IA were X=NR7, Y is a bond, and R2 is H and R1 is other than H, can be prepared as in Scheme 6. 
The starting isoquinolines 18 are either commercially available or they can be prepared by methods well known to those skilled in the art. Compound of formula 18 is treated with an appropriate alkylating or acylating reagent R7Xxe2x80x2, followed by the treatment of a reducing agent such as sodium borohydride to give 19 which is then converted to 1A with guanidine in an appropriate solvent such as dimethylformamide.
The compounds of formula IB (where X=NR7 and R1xe2x89xa0H and Y is a bond) may also be prepared as in Scheme 7. 
The starting anilines 20 are either commercially available or they can be prepared by methods well known to those skilled in the art. Compound of formula 20 can be treated with compounds of formula 21 to give 22. 22 may be cyclized to 23 using an appropriate reagent such as polyphosphoric acid or diphenylether. 23 may be further alkylated with an appropriate organometallic agent in the presence of a catalyst such as copper iodide to give 24. 24 may be treated with a reducing agent such as sodium borohydride followed by an acid such as hydrochloric acid to give 25 which is then converted to 1B with guanidine in an appropriate solvent such as dimethylformamide.
The compounds of formula I of the invention exhibit Na+/H+ exchange inhibitory activity, and hence, are useful for treating or preventing disorders caused by intracellular acidosis during myocardial ischemia, such as cardiac dysfunction, myocardial necrosis, arrhythmia, reperfusion injury, and the like which are observed in ischemic heart diseases (e.g., myocardial infarction and angina pectoris).
Thus, compounds of formula I of the invention may be used as antiischemic agents, i.e., for the treatment of ischemic conditions including acute and chronic ischemic conditions such as myocardial ischemia, cerebral ischemia, peripheral vascular diseases or disorders including lower limb ischemia peripheral atherosclerotic disease, tissue ischemia and intermittent claudication, LeRiches Syndrome and Raynaud""s disease. Thus, a composition containing one (or a combination) of the compounds of this invention, may be administered to a species of mammal (e.g., humans, dogs or cats) suffering from an ischemic condition or any of the conditions set out above.
A single dose, or two to four divided daily doses, provided on a basis of about 0.001 to about 100 mg per kilogram of body weight per day, preferably about 0.1 to about 25 mg per kilogram of body weight per day is appropriate. The substance is preferably administered orally, but parenteral routes such as the subcutaneous, intramuscular, intravenous or intraperitoneal routes or any other suitable delivery system, such as intranasal or transdermal routes can also be employed.
As a result of the Na+/H+ exchange inhibiting and antiischemic activity of the compounds of this invention, these compounds are also useful in the treatment of cardiovascular disorders. For example, compounds of the present invention are useful as therapy for congestive heart failure, intermittent claudication and therapy for hypertension, as anti-anginal agents, as antifibrillatory agents, and in limiting myocardial infarction.
Compounds of the present invention are additionally expected to be useful in the treatment of cerebral ischemia (e.g., stroke).
As a result of the Na/H exchange inhibiting activity, the compounds of this invention can also be used for the treatment of diseases associated with proliferation of smooth muscle cells, mesangial cells, and fibroblasts. Such diseases include restenosis after angioplasty, renal fibrosis, atherosclerosis, hepatic fibrosis, prostate hypertrophy, pulmonary fibrosis and glomerular nephrosclerosis.
Other uses for compounds of this invention which inhibit Na/H exchange and ischemia include treatments for diseases such as cardiac hypertrophy, ischemic/reperfusion injury associated with organ transplantation, and other surgical procedures such as percutaneous transluminal coronary angioplasty (PTCA).
Due to their Na/H exchange inhibiting and antiischemic properties, compounds of this invention can also be used for CNS disorders associated with cerebral ischemia such as cerebral infarction, cerebral edema and like. Additionally, they can be used for ischemia and ischemia-reperfusion injury resulting from shock and trauma.
The compounds of the invention are also anti-thrombotic agents and antiproliferative agents and are also useful in treating renal disease.
The compounds of the invention are also dual inhibitors of NHE-1 and NHE-3 and thus can be used as cardioprotectants for the treatment of heart disease, whilst also improving renal function by protecting against renal damage, or reversing hypertension by a direct modulation of sodium resorbtion in the kidney. As dual inhibitors, the compounds of the invention are also useful in a combination of therapies, for example, hypertension in patients with acute coronary syndromes, MI, recovery from MI and chronic stable angina. They are also useful for heart failure when an anti-hypertensive or diuretic agent is required for treatment.
Compounds of this invention can be additionally used for the treatment of diabetes mellitus and other diabetic complications and for lowering serum lipids such as lowering LDL-cholesterol.
The compounds of this invention can also be formulated in combination with a diuretic such as chlorothiazide, hydrochlorothiazide, flumethiazide, hydroflumethiazide, bendroflumethiazide, methylchlorthiazide, trichloromethiazide, polythiazide or benzthiazide as well as ethacrynic acid tricrynafen, chlorthalidone, furosemide, musolimine, bumetanide, triamterene, amiloride and spironolactone and salts of such compounds, angiotensin converting enzyme inhibitors such as captopril, zofenopril, fosinopril, enalapril, ceranopril, cilazopril, delapril, pentopril, quinapril, ramipril, lisinopril, and salts of such compounds, thrombolytic agents such as tissue plasminogen activator (tPA), recombinant tPA, streptokinase, urokinase, prourokinase, and anisoylated plasminogen streptokinase activator complex (APSAC, Eminase, Beecham Laboratories), or calcium channel blocking agents such as verapamil, nifedipine or diltiazem. Such combination products if formulated as a fixed dose employ the compounds of this invention within the dose range described above and the other pharmaceutically active agent within its approved dose range.
The compounds of formula I, and combinations thereof, can be formulated, as described above, in compositions such as tablets, capsules or elixirs for oral administration, in sterile solutions or suspensions for parenteral administration, and may also be administered via transdermal patch or nasal inhalation solutions. About 10 to about 500 milligrams of a compound of formula I is compounded with physiologically acceptable vehicle, carrier, excipient, binder, preservative, stabilizer, flavor, etc., in a unit dosage form as called for by accepted pharmaceutical practice. The amount of active substance in these compositions or preparations is such that a suitable dosage in the range indicated is obtained.